Renting a second camera for airshow

Well, I'm currently in the planning stages for a road trip down to Florida for the Sun N Fun flyin/airshow. I currently have in my kit, a 60D, 100-400L, Sigma 18-35, Tokina 11-16, 70-300 USM(non-L), Rokininon 85. I've been thinking about adding a FF to my kit setup(esp if by christmas time there isn't a 7D2 or similar out), and was thinking of renting a second body(5D3, or 6D), to play with during the shows. If I did get another body, I'd also be highly tempted to rent another long lens(400L... or if I was being really adventurous the 200-400).